I don't think it's about Facebook Ads sucking or not sucking. That's the narrative but the underlying issue is people feel that Facebook Ads are a rip off.

I wonder how much of Facebook's ad revenue (and Google's for that Matter) consists of less savvy marketing efforts that don't understand or even care about the metrics which matter. The long tail?

I don't believe the argument in favor of Facebook Ads can be that you need to understand marketing better or differently.

The majority, I presume, of people using these platforms have little to mediocre experience. The disappointment in Facebook Ads comes from this large group.

I've talked to plenty of people and no one has been happy with Facebook Ads. The details of why don't necessarily matter - they've taken their $ elsewhere. Winning them back will be tough.